This invention relates to improvement in precision wattmeters and is particularly suitable for use with thermal wattmeters
More specifically, the invention has been developed for use with a differential thermal wattmeter of the type disclosed in U.S. Pat. No. 4,045,734 issued Aug. 30, 1977 to L. G. Cox and N. L. Kusters, and will be exemplified below in connection with this type of wattmeter. Other similar circuits are decribed in greater detail, both as to structure and function, in "A Differential Thermal Wattmeter for the ac/dc Transfer of Power" by L. G. Cox and N. L. Kusters pp. 553-557, Vol. 1M-25, No. 4, December 1976, IEEE Transactions on Instrumentation and Measurement; and "The Development of an Automatic-Reversing Differential Thermal Wattmeter" by N. L. Kusters and L. G. Cox pp. 426-431, Vol. 1M-29, No. 4, December 1980, IEEE Transactions on Instrumentation and Measurement.
To enable the prior art to be explained with the aid of diagrams, the figures of the accompanying drawings will first be listed.